Electronic pen

ABSTRACT

An electronic pen includes a casing, an opening portion formed on one side of the casing, a core body that projects outside of the casing through the opening portion, a circuit board, and a core body insertion member disposed in the casing and having a hollow space that houses the core body. The hollow space includes a hollow portion between the core body insertion member and the core body when the core body insertion member houses the core body, the hollow portion communicating, via the opening portion, with a first space external to the electronic pen, and the hollow portion separated from a second space in which the circuit board is disposed.

BACKGROUND Technical Field

The present disclosure relates to an electronic pen that is used inconjunction with a position detecting device and which has a penpressure detecting function.

Description of Related Art

Recently, as an input device for a portable tablet, a personal computer,or the like, an input device has been used which includes an electronicpen (stylus pen) constituting a position indicator and a positiondetecting device having an input surface that receives pointingoperation and character and figure input by the electronic pen.

There are electronic pens of various types such as an electromagneticinduction type, a capacitive coupling type, and the like. However,electronic pens are generally configured to have a pen pressuredetecting function. An electronic pen of this type has an openingportion on one side in an axial direction of a casing of the electronicpen to project a front end of a rod-shaped core body from the openingportion, and has a space that allows the core body to move in the axialdirection in order to be able to transmit a pen pressure applied to thecore body to a pen pressure detector disposed within the casing.

There has recently been an increasing outdoor usage of tablets or thelike. However, as described above, the electronic pen is provided withthe opening portion in the casing to project the front end of the corebody to the outside, and in the case where the electronic pen has thepen pressure detecting function, the electronic pen has the spacecommunicating with the opening portion in order to allow the core bodyto move in the axial direction. Therefore, water and dust or the likemay enter the inside of the casing from the opening portion and thespace, affect electric parts and connecting portions housed within thecasing of the electronic pen, and consequently cause a failure in theelectronic pen.

Therefore, there has recently been a desire for a waterproof propertyand a dustproof property of the electronic pen, and various proposalshave been made in the past. For example, Japanese Patent Laid-Open No.2010-198193 (hereinafter referred to as Patent Document 1) discloses aconstitution in which, for example, a conically shaped rubber cap havinga through hole formed in a top portion thereof so as to fit closely to acore body is put on so as to cover an opening portion of a casing of anelectronic pen. In this constitution, the core body is attached throughthe through hole of the rubber cap and attached in a state in which afront end of the core body is projected.

According to this constitution, the opening portion of the casing iscovered by the rubber cap and is thus not exposed to the outside, and noair gap is formed between the core body and the rubber cap due to closecontact between the through hole and a side circumferential surfaceportion of the core body. Thus, a waterproof property and a dustproofproperty can be ensured.

However, in the case of Patent Document 1, the rubber cap is put ontothe opening portion side of the electronic pen so as not to expose theopening portion of the casing of the electronic pen to the outside.Therefore, the rubber cap itself is exposed to the outside, and may falloff. In addition, the rubber cap in Patent Document 1 has the throughhole in the top portion thereof. Thus, when the adhesion between thepart of the through hole and the core body is degraded, the effect ofthe waterproof property and the dustproof property may be reduced. Inparticular, in the constitution of Patent Document 1, the part ofcontact between the through hole in the top portion and the core body iselastically displaced according to movement in the axial direction ofthe core body which movement is caused by the application of a penpressure. Thus, the through hole in the top portion tends to be deformeddue to a secular change, and the adhesion between the through hole inthe top portion and the core body tends to become poor. The effect ofthe waterproof property and the dustproof property may therefore bereduced.

BRIEF SUMMARY

It is an object of the present disclosure to provide an electronic penthat can solve the problems described above and ensure a waterproofproperty and a dustproof property.

In order to solve the above problems, according to the presentdisclosure, there is provided an electronic pen including a tubularcasing, a rod-shaped core body that projects outside of the casingthrough an opening of the casing, the opening being formed on one sidein an axial direction of the casing, a pen pressure detector disposedwithin a hollow portion of the casing, wherein the pen pressuredetector, in operation, detects a pen pressure applied to the core body,a core body insertion member disposed between the pen pressure detectorand the opening of the casing within the hollow portion of the casing,the core body insertion member housing the core body movably in theaxial direction of the casing and having a hollow space closed on a sideof the pen pressure detector by a barrier that is elasticallydisplaceable in the axial direction of the casing, and a first sealingmember that separates the hollow space of the core body insertion memberfrom the hollow portion of the casing. A pen pressure applied to thecore body is transmitted to the pen pressure detector by elasticdisplacement of the barrier of the core body insertion member based onmovement of the core body in the axial direction of the casing withinthe hollow space of the core body insertion member according to the penpressure.

In the disclosure of the above-described constitution, the core bodyinsertion member is disposed between the pen pressure detector and theopening portion of the casing within the hollow portion of the casing,and the core body insertion member houses the core body movably in theaxial direction of the casing and has the hollow space closed on the penpressure detector side (opposite side from an opening side for insertionof the core body) by the barrier configured to be elasticallydisplaceable in the axial direction.

The hollow space of the core body insertion member and the space of thehollow portion of the casing are separated from each other by the firstsealing member. That is, the hollow space of the core body insertionmember is a space communicating with an external space of the electronicpen, but is closed by the barrier and is a space separate from the spaceof the hollow portion of the casing.

Hence, even in the constitution in which an opening portion of thehollow space of the core body insertion member (opening for insertion ofthe core body) into which the core body is inserted remains exposed tothe outside, the hollow space of the core body insertion member can beisolated from the inside of the space of the hollow portion of thecasing in which space electronic parts and electric connection parts arearranged. A waterproof property and a dustproof property can thereforebe ensured.

In the electronic pen according to the present disclosure, the core bodyis configured to move freely in the axial direction according to anapplied pen pressure within the hollow space of the core body insertionmember which hollow space is closed by the barrier, and transmit the penpressure to the pen pressure detector through elastic displacement ofthe barrier according to the movement in the axial direction of the corebody according to the pen pressure. Hence, the electronic pen accordingto the present disclosure does not have a part such as the rubber cap inthe case of Patent Document 1 described above, which part has the partof the through hole closely fitted to the core body and is elasticallydisplaced according to movement in the axial direction of the core body.Therefore, the electronic pen according to the present disclosure cansufficiently resist secular changes, and ensure a waterproof propertyand a dustproof property.

According to the present disclosure, it is possible to provide anelectronic pen that does not have a part including the part of a throughhole closely fitted to a core body and elastically displaced accordingto movement in the axial direction of the core body, and cansufficiently resist secular changes and ensure a waterproof property anda dustproof property.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an electronic apparatus and an electronic penused therewith according to one or more embodiments of the presentdisclosure;

FIG. 2 is an exploded perspective view of an internal configuration ofan electronic pen according to one or more embodiments of the presentdisclosure;

FIG. 3 is an exploded perspective view of a pen pressure detector of anelectronic pen according to one or more embodiments of the presentdisclosure;

FIGS. 4A, 4B, and 4C are diagrams of parts of a pressure sensor used ina pen pressure detector in an electronic pen according to one or moreembodiments of the present disclosure;

FIGS. 5A, 5B, and 5C are diagrams of parts of an internal configurationof an electronic pen according to one or more embodiments of the presentdisclosure;

FIG. 6 is a diagram of part of an internal configuration of anelectronic pen according to one or more embodiments of the presentdisclosure;

FIG. 7 is a diagram of parts of an internal configuration of anelectronic pen according to the present disclosure;

FIG. 8 is a diagram of parts of an internal configuration of anelectronic pen according to one or more embodiments of the presentdisclosure;

FIGS. 9A, 9B, and 9C are diagrams of parts of an internal configurationof an electronic pen according to one or more embodiments of the presentdisclosure;

FIG. 10 is a diagram showing an example circuit configuration of aposition detecting device used in conjunction with an electronic penaccording to one or more embodiments of the present disclosure;

FIG. 11 is a diagram of assistance in explaining an example ofconstitution of another embodiment of the electronic pen according toone or more embodiments of the present disclosure; and

FIG. 12 is a diagram showing an example circuit configuration of aposition detecting device used in conjunction with an electronic penaccording to one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

An electronic pen according to one or more embodiments of the presentdisclosure will hereinafter be described with reference to the drawings.The electronic pen is of a type that transmits an indicated position toa position detecting device by an electromagnetic induction system.

FIG. 1 shows an example of an electronic apparatus 200 that is used withan electronic pen 1 according to the present embodiment. In the presentexample, the electronic apparatus 200 is an advanced mobile telephoneterminal having a display screen 200D of a display device such as, forexample, a liquid crystal display (LCD) or the like. The electronicapparatus 200 includes a position detecting device 202 of anelectromagnetic induction type under (on the back side of) the displayscreen 200D.

The casing of the electronic apparatus 200 in the present example has ahousing recessed hole 201 in which the electronic pen 1 can be housed.As required, a user extracts the electronic pen 1 housed in the housingrecessed hole 201 from the electronic apparatus 200, and performs aposition indicating operation with the display screen 200D as an inputsurface.

In the electronic apparatus 200, when a position indicating operation isperformed on the display screen 200D by the electronic pen 1, theposition detecting device 202 disposed on the back side of the displayscreen 200D detects a position indicated by the electronic pen 1 and apen pressure, and a microcomputer included in the position detectingdevice 202 of the electronic apparatus 200 performs display processingaccording to the position indicated on the display screen 200D and thepen pressure.

In the electronic pen 1 according to the present embodiment, a pluralityof parts of the electronic pen 1 are arranged in an axial direction andhoused within a hollow portion of a tubular case (casing) 2 formed of aresin, for example. One side of the tubular case 2 has a tapered shape,and an end on the one side of the tubular case 2 has an opening (notshown in FIG. 1). A tip end portion 32 of a rod-shaped core body 3 to bedescribed later is exposed as a pen tip through the opening. A side ofthe case 2 that is opposite to the pen tip side is fitted with a casecap 21, and is thereby closed in a state in which sealing that takes awaterproof property and a dustproof property into account is ensured.

The electronic pen 1 in the present example has a side switch.Specifically, a printed circuit board is provided in the hollow portionwithin the case 2, as will be described later, and a side switch ismounted on the printed circuit board. A through hole (not shown in FIG.2) is bored in a side circumferential surface of the case 2 of theelectronic pen 1, which position corresponds to the side switch. Adepression operating element 22 for the side switch is exposed in thepart by the through hole so as to enable depression of the side switchmounted on the printed circuit board through the through hole. In thiscase, assignment and setting of a predetermined function to an operationof depressing the side switch by the depression operating element 22 aremade on the electronic apparatus 200 side including the positiondetecting device 202. For example, in the electronic apparatus 200 inthe present example, the operation of depressing the side switch by thedepression operating element 22 can be assigned and set as an operationsimilar to a clicking operation of a pointing device such as a mouse orthe like.

FIG. 2 is an exploded perspective view of parts housed within the case 2of the electronic pen 1, which are arranged separated from each other.In the present embodiment, an external shape in a direction orthogonalto the central axis of the case 2 (which external shape is equal to thecontour shape of a cross section of the case 2) is a flat shape. Thecross-sectional shape of the hollow portion within the case 2 also has aflat shape corresponding to the external shape of the case 2, and partshoused within the case 2 also have a shape corresponding to the flatshape of the hollow portion.

As shown in FIG. 2, arranged within the hollow portion of the case 2 inthe axial direction of the case 2 in order from the pen tip side are acap member 4 constituting a first sealing member, a coil member 5, acoil member holder 6, a pressing member 7, a pen pressure detector 8,and a board holder 9. A printed circuit board 10 is housed in and lockedto a board housing portion 91 of the board holder 9. The printed circuitboard 10 is an example of a circuit board.

A core body 3 is constituted of a core body main body portion 31 and atip end portion 32 as a pen tip. The core body 3 is attached byinserting the core body main body portion 31 from the opening on the pentip side of the case 2 and engaging the core body main body portion 31with the pressing member 7 disposed in the pen pressure detector 8, aswill be described later, in a state in which all of the above-describedparts are housed within the hollow portion of the case 2. The core body3 is formed of a resin as an example of a hard nonconductive material,for example polycarbonate, synthetic resin,acrylonitrile-butadiene-styrene (ABS) resin, or the like, so as to beable to transmit a pressure (pen pressure) applied to the tip endportion 32 to a pressure sensor 83 of a pen pressure detector 81. Thecore body 3 can be inserted into and detached from the electronic pen 1.

The coil member 5 is constituted of a coil 51 and a magnetic core aroundwhich the coil 51 is wound, which magnetic core is a ferrite core 52 inthe present example. The ferrite core 52 of the coil member 5 in thepresent example has a columnar shape having a through hole 52 a at aposition of the central axis, the through hole 52 a having a diameterslightly larger than the diameter of the core body main body portion 31so that the core body main body portion 31 of the rod-shaped core body 3can be inserted through the through hole 52 a. The ferrite core 52 inthe present embodiment has a flat cross-sectional shape corresponding tothe cross-sectional shape of the hollow portion of the case 2. A taperedportion 52 b that tapers off is formed on the pen tip side of theferrite core 52. Incidentally, the tip end portion 32 of the core body 3in the present example is formed so as to have a diameter slightlylarger than the diameter of the core body main body portion 31.

The cap member 4 is provided on the tapered portion 52 b side of theferrite core 52, the tapered portion 52 b side being on the pen tip sideof the electronic pen. The cap member 4 is formed of a material havingelasticity, for example, an elastic rubber. The cap member 4 has such acap shape as to cover the pen tip side of the ferrite core 52, and hasan opening (through hole) 4 a for insertion of the core body main bodyportion 31 of the core body 3. The diameter of the opening 4 a in thepresent example is formed so as to be larger than the diameter of thethrough hole 52 a of the ferrite core 52. The external appearance of thecap member 4 in the present example has a flared skirt shape, as shownin the figure.

The coil member holder 6 is provided on a side of the ferrite core 52that is opposite to the tapered portion 52 b on the pen tip side of theelectronic pen. The coil member holder 6 is formed of a material havingelasticity, for example, an elastic rubber. An end of the ferrite core52 that is opposite to the tapered portion 52 b on the pen tip side ofthe electronic pen is a coil non-wound portion 52 c on which the coil 51is not wound. The coil member holder 6 has a fitting portion 61 that isfitted with and houses the coil non-wound portion 52 c of the ferritecore 52, and has a projecting portion 62 press-fitted into a hollowportion 821 a of a pen pressure transmission member 82, which will bedescribed later, of the pen pressure detector 8.

The fitting portion 61 of the coil member holder 6 is provided with arecessed hole 61 a corresponding to the external shape of the coilnon-wound portion 52 c. A through hole 62 a (see FIGS. 5A and 5B to bedescribed later) through which the core body main body portion 31 of thecore body 3 is inserted is formed in the projecting portion 62. Thethrough hole 62 a of the projecting portion 62 communicates with therecessed hole 61 a of the fitting portion 61. Hence, a hollow spacethrough which the core body main body portion 31 of the core body 3 isinserted is formed through the fitting portion 61 and the projectingportion 62 in the coil member holder 6.

Because the through hole 52 a through which the core body main bodyportion 31 of the core body 3 is inserted is formed in the ferrite core52, a hollow space through which the core body main body portion 31 ofthe core body 3 is inserted is formed through the coil member 5 and thecoil member holder 6 in a state in which the coil non-wound portion 52 cof the ferrite core 52 of the coil member 5 is fitted in the fittingportion 61 of the coil member holder 6.

The pressing member 7 disposed on the projecting portion 62 side of thecoil member holder 6 has a fitting recessed hole 7 a (see FIG. 5A to bedescribed later) into which an end portion 31 a of the core body mainbody portion 31 of the core body 3 is press-fitted. The outside diameterof the pressing member 7 is selected to be larger than the through hole62 a of the projecting portion 62 of the coil member holder 6. Hence,the core body 3 does not fall off due to the presence of the pressingmember 7 when the end portion 31 a of the core body main body portion 31of the core body 3 is fitted in the pressing member 7 in a state inwhich the core body main body portion 31 of the core body 3 is insertedthrough the through hole 52 a of the ferrite core 52 of the coil member5, the recessed hole 61 a of the fitting portion 61 of the coil memberholder 6, and the through hole 62 a of the projecting portion 62, and inwhich state the end portion 31 a of the core body main body portion 31of the core body 3 is projected to the pressing member 7 side. However,when the core body 3 is strongly pulled to the tip end portion 32 side,the fit between the end portion 31 a of the core body main body portion31 and the fitting recessed hole 7 a of the pressing member 7 isreleased, so that the core body 3 can be extracted. Thus, the core body3 is replaceable.

The pen pressure detection module 8 in the present embodiment is formedby engaging and coupling the pen pressure detector 81 and the penpressure transmission member 82 with each other.

The pen pressure detector 81 in the present embodiment includes apressure sensor 83 constituted of a plurality of pressure sensing parts,and a holder 84 that retains the pressure sensor 83 and has a functionof making electric connections. The holder 84 is formed of an insulativematerial, for example, a resin. The holder 84 integrally includes aretaining portion 841 that retains the pressure sensor 83, and aconnecting portion 842 for electrically connecting two electrodes of thepressure sensor 83 retained by the retaining portion 841 to the printedcircuit board 10 housed in the board holder 9.

The pen pressure transmission member 82 makes the plurality of pressuresensing parts of the pressure sensor 83 retained by the retainingportion 841 of the holder 84 of the pen pressure detector 81 by engagingwith the retaining portion 841 of the holder 84. In addition, asdescribed earlier, the pen pressure transmission member 82 has thehollow portion 821 a into which the projecting portion 62 of the coilmember holder 6 is press-fitted. The projecting portion 62 of the coilmember holder 6 is press-fitted into the hollow portion 821 a of the penpressure transmission member 82 engaged and coupled with the penpressure detector 81. The pen pressure detection module 8 is therebycoupled with the coil member 5.

FIG. 3 is an exploded perspective view of assistance in explaining anexample constitution of the pen pressure detection module 8 in moredetail. FIGS. 4A, 4B, and 4C are diagrams of assistance in explaining agroup of pressure sensing parts constituting the pressure sensor 83.FIG. 5A is a sectional view of the pen pressure detection module 8 in astate of being housed within the case 2 and vicinities of the penpressure detection module 8. FIG. 5B is an external perspective view ofthe coil member holder 6 as viewed from the projecting portion 62 sideof the coil member holder 6. FIG. 5C is an external perspective view ofthe pen pressure transmission member 82 as viewed from the side of acoupling portion of the pen pressure transmission member 82 whichcoupling portion is coupled to the pen pressure detector 81.

As shown in FIG. 3 and FIGS. 4A to 4C, the pressure sensor 83 of the penpressure detector 81 in the present embodiment includes a dielectric831, a spacer 832, and a conductive elastic body 833.

As shown in FIG. 4A, the dielectric 831, for example, has substantiallythe shape of a disk. The dielectric 831 has one circular surface 831 aand another circular surface 831 b that face each other. A circularconductor layer 834 is formed on the one surface 831 a of the dielectric831. The conductor layer 834 constitutes a first electrode of a variablecapacitance capacitor as the pressure sensor 83 in the present example.

The spacer 832 is formed of an insulative material. As shown in FIG. 4B,the spacer 832 is a thin plate-shaped body having a ring shape whoseoutside diameter is equal to the diameter of the dielectric 831.

The conductive elastic body 833 in the present example is formed of anelastic rubber having conductivity. As shown in FIG. 4C, the conductiveelastic body 833 in the present example has a shape obtained by formingtwo projecting portions 833 b and 833 c from peripheral edges of a thinplate-shaped body 833 a having the shape of a disk whose outsidediameter is equal to the diameter of the dielectric 831, the peripheraledges of the plate-shaped body 833 a being separated from each other atan interval of 180 degrees. The spacer 832 is, for example, bonded tothe discoid plate-shaped body 833 a of the conductive elastic body 833.

Then, the variable capacitance capacitor as the pressure sensor 83 inthe present example is formed by superposing the conductive elastic body833 onto the other surface 831 b side of the dielectric 831 with thespacer 832 interposed therebetween. The variable capacitance capacitoras the pressure sensor 83 in the present example includes the firstelectrode constituted by the conductor layer 834 formed on the onesurface 831 a of the dielectric 831 and a second electrode constitutedby the conductive elastic body 833.

The holder 84 of the pen pressure detector 81 is configured, forexample, as an injection molded product produced by using resin, tointegrally include the retaining portion 841 and the connecting portion842. The connecting portion 842 of the holder 84 of the pen pressuredetector 81 includes a plate-shaped projecting portion 8421 thatprojects in the axial direction (same direction as a direction ofapplication of a pen pressure) parallel with a board surface 10 a of theprinted circuit board 10. The projecting portion 8421 has a flat surfaceparallel to the board surface 10 a of the printed circuit board 10. Theflat surface of the projecting portion 8421 is provided so as to comeinto contact with the board surface 10 a precisely when the pen pressuredetection module 8 is fitted into the board holder 9 and engaged withthe printed circuit board 10.

In the present embodiment, two terminal members 843 and 844 (hatched inFIG. 2 and FIG. 3 to facilitate understanding) are formed on the holder84 as conductive three-dimensional fine patterns from the retainingportion 841 to the connecting portion 842 along the direction ofapplication of a pen pressure, that is, the axial direction of theelectronic pen 1. As a result, the terminal members 843 and 844 areintegrally formed on the holder 84.

Here, microscopic integrated processing technology (MIPTEC) developed byPanasonic Corporation, for example, can be used as a method of formingthe two terminal members 843 and 844 as three-dimensional fine patternson the surface of the holder 84. In order to facilitate electricconnection by contact, nickel plating layers are formed on the surfacesof the terminal members 843 and 844 formed as three-dimensional finepatterns, and further gold plating layers are formed on the nickelplating layers.

As shown in FIG. 2 and FIG. 3, the two terminal members 843 and 844 areformed at two end edges of the projecting portion 8421, the end edgesbeing arranged in a direction orthogonal to the direction of applicationof a pen pressure, and are formed along long sides in the direction ofapplication of a pen pressure in a state of being separated from eachother. The two terminal members 843 and 844 are formed so as to beexposed at least at the two end edges of the projecting portion 8421.

The retaining portion 841 of the holder 84 of the pen pressure detector81 includes a recessed portion 841 a housing the pressure sensor 83 inwhich the dielectric 831, the spacer 832, and the conductive elasticbody 833 are coupled to each other, and includes engaging projectingportions 841 b, 841 c, 841 d, and 841 e projecting in the axialdirection from the recessed portion 841 a to the pen pressuretransmission member 82 side (core body 3 side). One end portion 844 a ofthe terminal member 844 is formed in an exposed state on a bottomportion of the recessed portion 841 a (see a hatched portion in FIG. 3).The dielectric 831 is housed such that the conductor layer 834 formed onthe one surface 831 a abuts against the one end portion 844 a of theterminal member 844 on the bottom portion of the recessed portion 841 a.Hence, in a state in which the dielectric 831 is housed and retainedwithin the recessed portion 841 a, the conductor layer 834 as the firstelectrode of the pressure sensor 83 and the one end portion 844 a of theterminal member 844 are in contact with each other and electricallyconnected to each other.

In addition, end surfaces against which the projecting portions 833 band 833 c of the conductive elastic body 833 abut are formed between theengaging projecting portions 841 b and 841 c of the retaining portion841 of the holder 84 of the pen pressure detector 81 and between theengaging projecting portions 841 d and 841 e of the retaining portion841. In the present embodiment, one end portion 843 a of the terminalmember 843 is formed in an exposed state on the end surface between theengaging projecting portions 841 b and 841 c (see a hatched portion inFIG. 3). Hence, in a state in which the conductive elastic body 833 ishoused and retained within the recessed portion 841 a of the holder 84together with the dielectric 831 and the spacer 832, the projectingportion 833 b of the conductive elastic body 833 abuts against the oneend portion 843 a of the terminal member 843. The conductive elasticbody 833 and the terminal member 843 are thereby in contact with eachother and electrically connected to each other.

Thus, in the present embodiment, when the pressure sensor 83 is housedand retained in the retaining portion 841 of the holder 84 of the penpressure detector 81, the first electrode and the second electrode ofthe pressure sensor 83 are automatically electrically connected to thetwo terminal members 843 and 844 of the connecting portion 842.

In the present embodiment, the two terminal members 843 and 844 of theconnecting portion 842 of the holder 84 of the pen pressure detector 81are configured to be electrically connected to conductive patternsformed on the printed circuit board 10 housed in the board holder 9.

The board holder 9 is formed of an insulative material, for example, aresin. The board holder 9 includes a board housing portion 91 and afitting portion 92 fitted with the holder 84 of the pen pressuredetector 81 of the pen pressure detector 8.

The board housing portion 91 of the board holder 9 is formed in theshape of a box without a lid. The printed circuit board 10 is housedwithin a recessed portion 91 a of the board housing portion 91 with thedirection of long sides of the elongate rectangular-shaped printedcircuit board 10 set in the axial direction of the electronic pen 1. Inthe present example, the depth of the recessed portion 91 a of the boardhousing portion 91 is substantially equal to the thickness of theprinted circuit board 10.

In addition, the fitting portion 92 of the board holder 9 in the presentembodiment has a tubular shape having a hollow portion into which theconnecting portion 842 of the holder 84 of the pen pressure detector 81of the pen pressure detection module 8 is inserted. The printed circuitboard 10 has conductor patterns 101 and 102 formed thereon, theconductor patterns 101 and 102 being positioned and formed so as to beelectrically connected to the two terminal members 843 and 844 of theconnecting portion 842 of the holder 84 of the pen pressure detector 81,the terminal members 843 and 844 being connected to the two electrodesof the pressure sensor 83 (see FIG. 2).

Then, when the connecting portion 842 of the holder 84 of the penpressure detection module 8 is inserted into the fitting portion 92 ofthe board holder 9, as shown in FIG. 5A, the connecting portion 842engages with the upper surface (board surface) 10 a of the printedcircuit board 10 housed in the board housing portion 91 of the boardholder 9 so as to be in contact with the upper surface (board surface)10 a. The two electrodes of the pressure sensor 83 retained by the penpressure detector 81 are thereby electrically connected to the conductorpatterns 101 and 102 formed on the board surface 10 a of the printedcircuit board 10 through the two terminal members 843 and 844 of theconnecting portion 842. The two terminal members 843 and 844 of theconnecting portion 842 of the holder 84 of the pen pressure detector 81of the pen pressure detection module 8 are in contact with andelectrically connected to the conductor patterns 101 and 102 on theprinted circuit board 10 by the fitting and coupling of the pen pressuredetector 81 of the pen pressure detection module 8 to the board holder 9and the printed circuit board 10. In the present embodiment, however,the two terminal members 843 and 844 are soldered to the conductorpatterns 101 and 102 to make the electric connections more secure.

Incidentally, the case cap 21 renders the board holder 9 non-movable inthe direction of application of a pen pressure applied to the core body3. Therefore, when the pen pressure detection module 8 is fitted to theboard holder 9, the pen pressure detection module 8 is prevented frombeing moved in the axial direction within the case 2 of the electronicpen 1. Hence, the pen pressure detector 81 can surely detect a penpressure applied to the core body.

In the present embodiment, as shown in FIG. 5A, the fitting portion 92of the board holder 9 is provided with a sealing member 93 that closes agap between the fitting portion 92 of the board holder 9 and an innerwall of the hollow portion of the case 2 when the sealing member 93 ishoused within the case 2. FIG. 6 shows an external appearance of thesealing member 93, which is formed by an elastic body, for example, aring-shaped member made of rubber. As shown in FIG. 5A, a ring-shapedrecessed groove 92 a is formed in a circumferential side portion of thefitting portion 92 of the board holder 9. The sealing member 93 is fixedand housed within the ring-shaped recessed groove 92 a. Incidentally, inthe present embodiment, projections 93 a are formed on the sealingmember 93 so as to prevent the sealing member 93 from rotating in thecircumferential direction of the fitting portion 92, and notches 92 b(see FIG. 5A) that house the projections 93 a of the sealing member 93are formed in a part of the ring-shaped recessed groove of the fittingportion 92.

The sealing member 93 separates a space in which the printed circuitboard 10 is disposed in the hollow portion within the case 2 from aspace on an opening portion 2 a side in which space the pen pressuredetection module 8 is present and from which space the core body 3 isprojected. Hence, the sealing member 93 corresponds to a second sealingmember.

The electronic pen 1 according to the present embodiment uses aresonance circuit constituted of the coil 51 wound around the ferritecore 52 of the coil member 5 and a capacitor in order to transmit aposition indicated by the electronic pen 1 to the position detectingdevice. The capacitor 103 constituting the resonance circuit is formedon the board surface 10 a of the printed circuit board 10, as shown inFIG. 2. In addition, a side switch 104 formed by a depression switchthat is turned on and off by being depressed is provided on the boardsurface 10 a of the printed circuit board 10. Further, a capacitor 105connected in series with the side switch 104 and other electronic partsare arranged on the board surface 10 a of the printed circuit board 10.

Incidentally, a series circuit of the side switch 104 and the capacitor105 is connected in parallel with the resonance circuit formed by thecoil 51 and the capacitor 103, and changes the resonance frequency ofthe resonance circuit according to the turning on or off of the sideswitch 104, thereby notifying the position detecting device 202 whetherthe side switch 104 is turned on or remains off.

As described earlier, the pen pressure detector 81 of the pen pressuredetection module 8 according to the present embodiment uses, as thepressure sensor 83, the variable capacitance capacitor that exhibits acapacitance corresponding to a pen pressure. The electronic pen 1 makesthe resonance frequency of the resonance circuit correspond to the penpressure because the variable capacitance capacitor of the pressuresensor 83 of the pen pressure detector 81 of the pen pressure detectionmodule 8 is connected to the resonance circuit.

The position detecting device 202 compatible with the electronic pen 1has a function of detecting a pen pressure applied to the pen tip of theelectronic pen 1 by detecting a change in the resonance frequency of anelectromagnetic coupling signal from the electronic pen 1. The conductorpatterns 101 and 102 described above constitute terminal portions forconnecting the variable capacitance capacitor formed by the pressuresensor 83 of the pen pressure detector 81 of the pen pressure detectionmodule 8 to the resonance circuit.

As shown in FIGS. 5A and 5C, the pen pressure transmission member 82 ofthe pen pressure detection module 8 is constructed by integrally forminga tubular body portion 821 having the hollow portion 821 a therewithinand a barrier 822 that closes the hollow space of the hollow portion 821a of the tubular body portion 821.

The barrier 822 in the present example is formed by a thin plate-shapedbody. As shown in FIGS. 5A and 5C, recessed portions 822 a and 822 b areformed in the thin plate-shaped body. Thus, because of thin-walledportions formed by reduced thickness of the parts of the recessedportions 822 a and 822 b, the barrier 822 is elastically displaced in adirection of the plate thickness. In the present embodiment, the barrier822 is formed by an elastic member, for example, an elastomer, which,coupled with the thin-walled portions of the parts of the recessedportions 822 a and 822 b, facilitates the elastic displacement of thebarrier 822 in the direction of the plate thickness.

The tubular body portion 821 may be formed by a material not havingelasticity, for example, a resin, or may be formed by an elastomer, asin the case of the barrier 822. In a case where the tubular body portion821 is formed of a material not having elasticity and the barrier 822 isformed of an elastomer having elasticity, the pen pressure transmissionmember 82 may be manufactured by a method of two-color molding.

An opening portion is formed on a side of the hollow portion 821 a ofthe tubular body portion 821 on which side the barrier 822 is notprovided. The projecting portion 62 of the coil member holder 6 ispress-fitted from the opening portion side into the hollow portion 821a. In the present example, the side circumferential surface of theprojecting portion 62 of the coil member holder 6 is provided with tworing-shaped projecting portions 621 and 622 as shown in FIGS. 5A and 5B.The coil member holder 6 is fitted into the pen pressure transmissionmember 82 without a gap being formed between the inner wall of the penpressure transmission member 82 and the projecting portion 62 of thecoil member holder 6 due to the ring-shaped projecting portions 621 and622. Incidentally, while the two ring-shaped projecting portions 621 and622 are formed on the projecting portion 62 in the present example, onering-shaped projecting portion may suffice.

Prior to the press-fitting of the coil member holder 6, the pressingmember 7 is housed within the hollow portion 821 a of the pen pressuretransmission member 82 such that the fitting recessed hole 7 a isoriented toward the opening side of the tubular body portion 821 and aside of the pressing member 7 that is opposite to the fitting recessedhole 7 a abuts against the barrier 822 of the pen pressure transmissionmember 82. The outside diameter of the pressing member 7 is larger thanthe through hole 62 a of the projecting portion 62 of the coil memberholder 6. Thus, when the coil member holder 6 is press-fitted into thehollow portion 821 a of the pen pressure transmission member 82, thepressing member 7 is housed within the hollow portion 821 a of the penpressure transmission member 82 without falling off the hollow portion821 a.

Then, when the core body main body portion 31 of the core body 3 isinserted through the through hole 52 a of the ferrite core 52 of thecoil member 5, the recessed hole 61 a of the fitting portion 61 of thecoil member holder 6, and the through hole 62 a of the projectingportion 62, and pushed in, the end portion 31 a of the core body mainbody portion 31 of the core body 3 is press-fitted into the fittingrecessed hole 7 a of the pressing member 7 in the hollow portion 821 aof the pen pressure transmission member 82, as shown in FIG. 5A.

Hence, when a pen pressure is applied to the core body 3, the penpressure is transmitted to the pressing member 7, the pressing member 7presses the barrier 822 of the pen pressure transmission member 82, andthe barrier 822 is elastically displaced in the axial directionaccording to the applied pen pressure.

As described above, when the coil member 5 is fitted to the pen pressuretransmission member 82 via the coil member holder 6, the through hole 52a of the ferrite core 52 of the coil member 5, the recessed hole 61 a ofthe fitting portion 61 of the coil member holder 6, and the through hole62 a of the projecting portion 62 communicate with each other to form ahollow space through which to insert the core body main body portion 31of the core body 3. This hollow space is closed by the barrier 822 ofthe pen pressure transmission member 82. That is, in the presentexample, a core body insertion member is formed by fitting and couplingthe coil member 5, the coil member holder 6, and the pen pressuretransmission member 82 with each other.

The tubular body portion 821 of the pen pressure transmission member 82also has an engaging projection 823 a and an engaging projection 823 bformed thereon, the engaging projection 823 a being engaged with theengaging projecting portion 841 b and the engaging projecting portion841 c of the retaining portion 841 of the holder 84 of the pen pressuredetector 81, and the engaging projection 823 b being engaged with theengaging projecting portion 841 d and the engaging projecting portion841 e. An engaging pawl portion 841 bt and an engaging pawl portion 841ct to be engaged with the engaging projection 823 a are formed at endsof the engaging projecting portion 841 b and the engaging projectingportion 841 c of the retaining portion 841 of the holder 84. Inaddition, an engaging pawl portion 841 dt and an engaging pawl portion841 et to be engaged with the engaging projection 823 b are formed atends of the engaging projecting portion 841 d and the engagingprojecting portion 841 e.

Then, when the pen pressure transmission member 82 is coupled to theholder 84 in the axial direction in a state in which the pressure sensor83 is housed in the retaining portion 841 of the holder 84, the penpressure transmission member 82 and the holder 84 are coupled to eachother, and thereby the pressure sensor 83 is retained by the retainingportion 841 of the holder 84, as shown in FIG. 2. At this time, theengaging pawl portion 841 bt and the engaging pawl portion 841 ct at theends of the engaging projecting portion 841 b and the engagingprojecting portion 841 c of the retaining portion 841 of the holder 84are engaged with the engaging projection 823 a of the pen pressuretransmission member 82, and the engaging pawl portion 841 dt and theengaging pawl portion 841 et at the ends of the engaging projectingportion 841 d and the engaging projecting portion 841 e are engaged withthe engaging projection 823 b. The pen pressure transmission member 82is thus engaged with the retaining portion 841 of the holder 84.Thereby, the pen pressure transmission member 82 is locked to the holder84, and the pen pressure transmission member 82 and the holder 84 arecoupled to each other.

In the state in which the pen pressure transmission member 82 is thusengaged with and coupled to the holder 84, as shown in FIG. 3, in theretaining portion 841 of the holder 84 of the pen pressure detector 81,as described earlier, the conductor layer 834 (first electrode) on theone end surface of the dielectric 831 of the pressure sensor 83 iselectrically connected to the one end portion 844 a of the terminalmember 844, and the projecting portion 833 b of the conductive elasticbody 833 (second electrode) is electrically connected to the one endportion 843 a of the terminal member 843.

In the state in which the pen pressure transmission member 82 is engagedwith and coupled to the holder 84, as shown in FIG. 5A, the barrier 822of the pen pressure transmission member 82 can press the conductiveelastic body 833 of the pressure sensor 83. Incidentally, in the presentembodiment, as shown in FIG. 5C, an end 823 at of the engagingprojection 823 a of the pen pressure transmission member 82 which end ison the barrier 822 side and an end 823 bt of the engaging projection 823b which end is on the barrier 822 side are formed obliquely so as toproject slightly from the surface of the barrier 822 in the axialdirection. Therefore, because of the presence of the end 823 at of theengaging projection 823 a of the pen pressure transmission member 82which end is on the barrier 822 side and the end 823 bt of the engagingprojection 823 b which end is on the barrier 822 side, when no penpressure is applied, the barrier 822 faces the conductive elastic body833 of the pressure sensor 83 with a small space interposedtherebetween, as shown in FIG. 5A.

Then, as described above, when a pen pressure is applied to the corebody 3, the barrier 822 of the pen pressure transmission member 82 ispressed by the pressing member 7 according to the applied pen pressure,and the barrier 822 is elastically displaced in the axial directionaccording to the applied pen pressure. The conductive elastic body 833of the pressure sensor 83 is pressed by the elastic displacement of thebarrier 822. Therefore, the conductive elastic body 833 and thedielectric 831 separated from each other via the spacer 832 come intocontact with each other, and the area of the contact changes accordingto the pen pressure. A capacitance corresponding to the area of thecontact between the conductive elastic body 833 and the dielectric 831is obtained between the first electrode and the second electrode of thepressure sensor 83. That is, the pen pressure can be detected from thecapacitance of the variable capacitance capacitor as the pressure sensor83.

As described above, the coil member 5 is fitted and coupled to the penpressure transmission member 82 of the pen pressure detection module 8via the coil member holder 6, and then the connecting portion 842 of theholder 84 of the pen pressure detector 81 of the pen pressure detection8 is coupled to the printed circuit board 10 via the fitting portion 92of the board holder 9. Thus, the coil member 5 constituted of theferrite core 52 wound with the coil 51, the pen pressure detectionmodule 8, and the board holder 9 retaining the printed circuit board 10are coupled to each other to form one module (pen module part).

After the pen pressure detection module 8 and the board holder 9 housingthe printed circuit board 10 are fitted and coupled to each other, asshown in FIG. 7, one end portion 51 a and another end portion 51 b ofthe coil 51 of the coil member 5 are, for example, soldered andconnected to the terminal member 843 and the terminal member 844 atparts of the connecting portion 842 of the holder 84 of the pen pressuredetector 81 which parts are fitted in the fitting portion 92 of theboard holder 9. Parts filled in black in FIG. 7 represent the solderedparts.

In the present embodiment, as shown in FIG. 2 and FIG. 7, a notch 92 aand a notch 92 b are formed in the fitting portion 92 of the boardholder 9 so that the parts of connection (soldered parts) of the one endportion 51 a and the other end portion 51 b of the coil 51 to theterminal member 843 and the terminal member 844 do not obstruct thefitting of the fitting portion 92 of the board holder 9 with the penpressure detector 8.

In addition, in the present embodiment, a recessed groove 824 a and arecessed groove 824 b in the axial direction are formed in the penpressure transmission member 82 of the pen pressure detector 8, and arecessed groove 845 a and a recessed groove 845 b in the axial directionwhich recessed grooves are in line with the recessed groove 824 a andthe recessed groove 824 b of the pen pressure transmission member 82 arealso formed in the peripheral side surface of the holder 84 of the penpressure detector 81. As shown in FIG. 7, the one end portion 51 a andthe other end portion 51 b of the coil 51 of the coil member 5 passthrough the insides of the recessed groove 824 a and the recessed groove824 b and the recessed groove 845 a and the recessed groove 845 b, andare soldered and connected to the terminal member 843 and the terminalmember 844 of the connecting portion 842 of the holder 84 of the penpressure detector 81.

The one end portion 51 a and the other end portion 51 b of the coil 51of the coil member 5 are thus prevented from protruding in a directionorthogonal to the axial direction in the pen module part. Further, inthe present example, as shown in FIG. 5B, a stepped portion 61 b and astepped portion 61 c for preventing the one end portion 51 a and theother end portion 51 b of the coil from protruding from the pen modulepart are formed in the outer peripheral portion of the fitting portion61 of the coil member holder 6.

Incidentally, instead of simply soldering the one end portion 51 a andthe other end portion 51 b of the coil 51 to the terminal member 843 andthe terminal member 844, V-shaped metal terminals or the like may beformed at the positions of the terminal member 843 and the terminalmember 844 in advance, and the one end portion 51 a and the other endportion 51 b of the coil 51 may be engaged with the V-shaped metalterminals. Also in that case, soldering may be performed to make theelectric connections more securely.

When the one end portion 51 a and the other end portion 51 b of the coil51 are thus electrically connected to the terminal member 843 and theterminal member 844, the resonance circuit is formed because theterminal member 843 and the terminal member 844 are connected to thecapacitor 103 on the printed circuit board 10, and the variablecapacitance capacitor formed by the pressure sensor 83 is connected inparallel with the resonance circuit. This eliminates a need forextending the one end portion 51 a and the other end portion 51 b of thecoil 51 to the printed circuit board 10 and soldering the one endportion 51 a and the other end portion 51 b of the coil 51 on the boardsurface 10 a of the printed circuit board 10.

After the pen pressure detection module 8 and the board holder 9retaining the printed circuit board 10 are coupled to each other asdescribed above, the parts of connection of the terminal member 843 andthe terminal member 844 of the connecting portion 842 of the penpressure detector 81 to the conductor pattern 101 and the conductorpattern 102 on the board surface 10 a of the printed circuit board 10are soldered as required. Thereafter, as shown in FIG. 5A and FIG. 9A, aresin molded member 110 covers the board surface 10 a of the printedcircuit board 10 housed in the board housing portion 91 of the boardholder 9, with the exclusion of the part of the side switch 104 toenable the pressing of the side switch 104.

Then, the pen module part, in which the coil member 5, the pen pressuredetector 8, and the board holder 9 retaining the printed circuit board10 described above are coupled to each other to form one module, ishoused within the hollow portion of the case 2 of the electronic pen 1.The depression operating element 22 that depresses the side switch 104is attached at the time of housing the pen module part into the hollowportion of the case 2.

FIG. 9A is a sectional view of a part in which the board holder 9 ishoused within the case 2. In addition, FIG. 9B is a view of anattachment member 23 for the side switch 104, the attachment member 23being viewed from a surface side thereof opposed to the printed circuitboard 10. In addition, FIG. 9C is a view of the depression operatingelement 22 for the side switch 104, the depression operating element 22being viewed from a surface side thereof opposed to the printed circuitboard 10.

As shown in FIG. 9A, a through hole 2 b for disposing the depressionoperating element 22 is formed in the case 2. The depression operatingelement 22 is formed of a resin, for example. As shown in FIG. 9C, thedepression operating element 22 is formed in a shape that precisely fitsinto the through hole 2 b of the case 2. As shown in FIGS. 9A and 9C,cylindrical projecting portions 221 and 222 engaged with the attachmentmember 23 are formed on a surface of the depression operating element 22which surface is opposite the printed circuit board 10.

The attachment member 23 is formed of a material having elasticity, or aresin in the present example. Through holes 231 and 232 with which theprojecting portions 221 and 222 of the depression operating element 22are engaged are formed in the attachment member 23, and a projectingportion 233 for depression of the side switch 104 is formed on theattachment member 23. The through holes 231 and 232 of the attachmentmember 23 include circular parts 231 a and 232 a having a same diameteras the diameter of the projecting portions 221 and 222 of the depressionoperating element 22, and linear holes 231 b and 232 b having a widthshorter than the diameter of the projecting portions 221 and 222.

Formed at base positions of the cylindrical projecting portions 221 and222 of the depression operating element 22 are cutaway portions 221 aand 222 a (see dotted lines in FIG. 9C) that engage with the linearholes 231 b and 232 b of the through holes 231 and 232 of the attachmentmember 23 so that the depression operating element 22 does not fall offthe attachment member 23. Incidentally, the linear holes 231 b and 232 bof the through holes 231 and 232 of the attachment member 23 are formedso as to be slightly thinner than the other parts of the attachmentmember 23, in accordance with the cutaway portions 221 a and 222 b atthe base positions of the cylindrical projecting portions 221 and 222 ofthe depression operating element 22.

As shown in FIG. 9A and FIG. 2, a recessed hole 91 b for locking theattachment member 23 is provided at an end portion of the board holder 9which end portion is on the case cap 21 side. On the other hand, asshown in FIGS. 9A and 9B, a bent projecting portion 234 fitted in therecessed hole 91 b is formed on an end portion in a longitudinaldirection of the attachment member 23.

Prior to housing of the pen module part into the case 2, as shown inFIG. 9A, the projecting portion 233 of the attachment member 23 is setin a state of being able to depress the side switch 104, the bentprojecting portion 234 of the attachment member 23 is fitted into therecessed hole 91 b of the board holder 9, and the attachment member 23is attached onto the printed circuit board 10 covered by the resinmolded member 110 in the board holder 9.

Next, the pen module part to which the attachment member 23 is attachedis housed into the case 2 from an opposite side from an opening portion2 a on the pen tip side. Then, when the parts of the through holes 231and 232 of the attachment member 23 attached to the pen module part canbe seen from the through hole 2 b of the case 2, the depressionoperating element 22 is inserted into the through hole 2 b of the case2, and the projecting portions 221 and 222 of the depression operatingelement 22 are inserted into and engaged with the circular parts 231 aand 232 a of the through holes 231 and 232 of the attachment member 23.

The pen module part is further pushed into the case 2. Then, theprojecting portions 221 and 222 of the depression operating element 22which projecting portions are inserted in the circular parts 231 a and232 a of the through holes 231 and 232 of the attachment member 23 areengaged with the linear holes 231 b and 232 b of the through holes 231and 232 of the attachment member 23. Thus, the depression operatingelement 22 is engaged with the attachment member 23, and is preventedfrom falling off the attachment member 23. As described above, thedepression operating element 22 is attached by being engaged with theattachment member 23 when the pen module part is housed into the case 2.

In this case, as described earlier, in the vicinity of an openingportion of the pen module part which opening portion is on the pen tipside of the hollow portion of the case 2, the cap member 4 is disposedin such a manner as to cover the tapered portion 52 b of the ferritecore 52. As described earlier, the cap member 4 is formed of an elasticrubber, and constitutes a first sealing member that provides sealing soas to eliminate a gap between the front end side of the ferrite core 52of the coil member 5 and the inner wall surface of the hollow portion ofthe case 2.

FIG. 8 is a sectional view showing the opening portion 2 a side of thecase 2 of the electronic pen 1 when the pen module part is housed in thehollow portion within the case 2. In this case, the pen module part ispressed to the opening portion 2 a side of the case 2 by the case cap 21when the case cap 21 is fitted to the case 2. The tapered portion 52 bof the ferrite core 52 of the coil member 5 therefore presses the capmember 4 to the inner wall side of the case 2. Sealing is therebyprovided so as to eliminate the gap between the tapered portion 52 b andthe inner wall of the case 2. The cap member 4 in the present examplehas a flared skirt shape, as described above. Therefore, as shown inFIG. 8, the cap member 4 and the inner wall surface of the case 2 are inclose contact with each other at two positions, so that a dustproofeffect and a waterproof effect of the sealing are improved.

The sealing by the cap member 4 on the opening portion 2 a side of thecase 2 separates the space of the through hole 52 a of the ferrite core52 from the space of the hollow portion in which the pen module part ishoused within the case 2.

That is, as described earlier, in the present example, the coil member5, the coil member holder 6, and the pen pressure transmission member 82are fitted and coupled to each other, and thereby constitute the corebody insertion member. The hollow space of the core body insertionmember is constituted of the through hole 52 a of the ferrite core 52 ofthe coil member 5, the recessed hole 61 a and the through hole 62 a ofthe coil member holder 6, and the hollow portion 821 a of the penpressure transmission member 82, and is closed by the barrier 822 of thepen pressure transmission member 82.

In this case, in a fitting portion in which the projecting portion 62 ofthe coil member holder 6 is fitted in the pen pressure transmissionmember 82, the ring-shaped projecting portions 621 and 622 of the coilmember holder 6 are in close contact with the inner wall of the hollowportion 821 a of the pen pressure transmission member 82 without a gaptherebetween, so that sealing is ensured. Thus, the hollow space of thecore body insertion member is an independent space isolated from therest, except for the opening side of the through hole 52 a of theferrite core 52. Neither electric parts nor electric connection partsare present within the hollow space of the core body insertion member.It is therefore unnecessary to ensure a waterproof property and adustproof property in the hollow space of the core body insertionmember.

On the tapered portion 52 b side of the ferrite core 52 which taperedportion is an end portion on the tip end portion 32 side of the corebody insertion member, as described above with reference to FIG. 8, thesealing between the tapered portion 52 b side of the ferrite core 52 andthe inner wall of the case 2, which sealing is provided by the capmember 4, separates the hollow space of the core body insertion memberfrom the space of the hollow portion in which the pen module part ishoused within the case 2.

Hence, even when dust or water enters the hollow space of the core bodyinsertion member, the dust or the water does not enter the space of thehollow portion in which the pen module part is housed within the case 2.Therefore, it becomes unnecessary to provide sealing between the corebody 3 and the hollow space of the core body insertion member, and awaterproof property and a dustproof property of the electronic pen 1 canbe ensured even when the core body 3 is freely moved in the axialdirection.

In a state in which the pen module part is housed within the case 2, asshown in FIG. 5A and FIG. 9A, the sealing member 93 provided on thefitting portion 92 of the board holder 9 which fitting portion is fittedwith the pen pressure detection module 8 is in close contact with theinner wall surface of the case 2, and provides sealing so as to separatethe hollow portion of the case 2 into the pen tip side of the fittingportion 92 and the case cap 21 side of the fitting portion 92.

As described earlier, on the pen tip side, the cap member 4 seals offthe space of the hollow portion of the case 2 from the external space.Hence, a space on the pen tip side of the fitting portion 92 in thehollow portion within the case 2 is a sealed space in which a waterproofproperty and a dustproof property are ensured by first sealing by thecap member 4 and second sealing by the sealing member 93 of the fittingportion 92.

Hence, water and dust from the external space on the opening portion 2 aside as the pen tip side of the electronic pen 1 are prevented fromentering the space on the pen tip side of the fitting portion 92 in thehollow portion within the case 2, and water and dust are prevented fromentering through the through hole 2 b in the part in which thedepression operating element 22 for the side switch 104 is disposed. Asdescribed above, the pressure sensor 83 is disposed in the space on thepen tip side of the fitting portion 92 in the hollow portion within thecase 2, and also arranged therein are the parts of connection of thecoil 51 to the pressure sensor 83 and the parts of connection to thecapacitor 103, the side switch 104, and the capacitor 105 on the printedcircuit board 10. A waterproof property and a dustproof property ofthese parts can be ensured.

On the case cap 21 side of the fitting portion 92 in the hollow portionwithin the case 2, the resin molded member 110 covers the board surface10 a of the printed circuit board 10. Thus, even when water and dustenter through the through hole 2 b in the part in which the depressionoperating element 22 for the side switch 104 is disposed, a waterproofproperty and a dustproof property of electronic parts on the boardsurface 10 a of the printed circuit board 10 are ensured.

Incidentally, in the present embodiment, as a result of the coil member5 being fitted to the pen pressure transmission member 82 of the penpressure detection module 8 via the coil member holder 6, the centerline position in the axial direction of the pen pressure detectionmodule 8 and the center line position in the axial direction of theferrite core 52 of the coil member 5 coincide with each other. Then,when the pen pressure detection module 8 is fitted to the fittingportion 92 of the board holder 9, and the pen pressure detection module8 is thereby coupled to the printed circuit board 10, the pen pressuredetection module 8 is coupled at a predetermined position to the boardholder 9 and the printed circuit board 10. In addition, in a state inwhich the pen module part is housed within the hollow portion of thecase 2, the board holder 9 is coupled to the case cap 21 such that thecenter line position in the axial direction of the pen pressuredetection module 8 and the center line position in the axial directionof the ferrite core 52 coincide with the center line position in theaxial direction of the hollow portion of the case 2.

Then, the core body main body portion 31 of the core body 3 is insertedthrough the opening portion 2 a (see FIG. 8) of the case 2 and theopening 4 a of the cap member 4 and further inserted through the throughhole 52 a of the ferrite core 52, and is fitted into the pressing member7 within the pen pressure transmission member 82 of the pen pressuredetection module 8.

As described above, according to the present embodiment, the firstsealing and the second sealing for a waterproof property and a dustproofproperty of the electronic pen 1 can be provided by merely housing thepen module part within the case 2. According to the present embodiment,the hollow space of the core body insertion member formed by the coilmember 5, the coil member holder 6, and the pen pressure transmissionmember 82 of the pen pressure detection module 8 is not sealed off fromthe outside. The core body 3 can therefore move freely in the axialdirection.

According to the above-described embodiment, by merely fitting the penpressure detection module 8 to the board holder 9 to which the printedcircuit board 10 is locked, the two terminal members 843 and 844 of thepen pressure detector 8 are in contact with and electrically connectedto the conductor patterns 101 and 102 formed on the board surface 10 aof the printed circuit board 10. That is, alignment for electricconnection between the two terminal members 843 and 844 of the penpressure detection module 8 and the conductor patterns 101 and 102 onthe printed circuit board 10 is automatically performed by merelyfitting the pen pressure detection module 8 to the fitting portion 92 ofthe board holder 9.

[Circuit Configuration for Detecting Position and Pen Pressure ofElectronic Pen 1 in Position Detecting Device 202]

An example of a circuit configuration in the position detecting device202 that detects an indicated position and detects a pen pressure byusing the electronic pen 1 according to the above-described embodimentwill next be described with reference to FIG. 10. FIG. 10 is a blockdiagram showing an example of circuit configuration of the positiondetecting device 202 in the present example.

The electronic pen 1 includes a resonance circuit 1R formed by aparallel circuit of the coil 51, the capacitor 103, a variablecapacitance capacitor 83C formed by the pressure sensor 83 of the penpressure detector 81 of the pen pressure detector 8, and a seriescircuit of the side switch 104 and the capacitor 105. In this case, thecapacitance of the variable capacitance capacitor 83C formed by thepressure sensor 83 of the pen pressure detector 81 changes according toan applied pen pressure. The resonance frequency of the resonancecircuit 1R therefore changes according to the pen pressure. In addition,the resonance frequency of the resonance circuit 1R is changed bycontrolling whether or not to connect the capacitor 105 to the resonancecircuit 1R by turning the side switch 104 on or off.

The position detecting device 202 detects a position on a sensor whichposition is indicated by the electronic pen 1 from a position on thesensor where a signal received from the resonance circuit 1R of theelectronic pen 1 by electromagnetic coupling is detected, and detects apen pressure applied to the core body 3 of the electronic pen 1 bydetecting a change in phase of the signal received from the resonancecircuit 1R of the electronic pen 1 by electromagnetic coupling andthereby detecting a change in the resonance frequency.

The position detecting device 202 has a position detecting coil 240formed thereon by stacking an X-axis direction loop coil group 241 and aY-axis direction loop coil group 242. The position detecting device 202is also provided with a selection circuit 243 to which the X-axisdirection loop coil group 241 and the Y-axis direction loop coil group242 are connected. The selection circuit 243 sequentially selects oneloop coil of the two loop coil groups 241 and 242.

The position detecting device 202 further includes an oscillator 251, acurrent driver 252, a switching connecting circuit 253, a receivingamplifier 254, a detector 255, a low-pass filter 256, a sample and holdcircuit 257, an analog to digital (A/D) conversion conversion circuit258, a synchronous detector 259, a low-pass filter 260, a sample andhold circuit 261, an A/D conversion circuit 262, and a processingcontrol circuit 263. The processing control circuit 263 is formed by amicrocomputer.

The oscillator 251 generates an alternating-current signal of afrequency f0. The oscillator 251 then supplies the generatedalternating-current signal to the current driver 252 and the synchronousdetector 259. The current driver 252 converts the alternating-currentsignal supplied from the oscillator 251 into a current, and sends outthe current to the switching connecting circuit 253. The switchingconnecting circuit 253 selects a connection destination (a transmissionside terminal T or a receiving side terminal R) to which to connect theloop coil selected by the selection circuit 243, under control of theprocessing control circuit 263. Of the connection destinations, thetransmission side terminal T is connected with the current driver 252,and the receiving side terminal R is connected with the receivingamplifier 254.

An induced voltage generated in the loop coil selected by the selectioncircuit 243 is sent to the receiving amplifier 254 via the selectioncircuit 243 and the switching connecting circuit 253. The receivingamplifier 254 amplifies the induced voltage supplied from the loop coil,and sends out the amplified induced voltage to the detector 255 and thesynchronous detector 259.

The detector 255 detects the induced voltage generated in the loop coil,that is, a received signal, and sends out the received signal to thelow-pass filter 256. The low-pass filter 256 has a cutoff frequencysufficiently lower than the above-mentioned frequency f0. The low-passfilter 256 converts the output signal of the detector 255 into adirect-current signal, and sends out the direct-current signal to thesample and hold circuit 257. The sample and hold circuit 257 holds avoltage value of the output signal of the low-pass filter 256 inpredetermined timing, specifically predetermined timing during areception period, and sends out the voltage value to the A/D conversioncircuit 258. The A/D conversion circuit 258 converts the analog outputof the sample and hold circuit 257 into a digital signal, and outputsthe digital signal to the processing control circuit 263.

Meanwhile, the synchronous detector 259 performs synchronous detectionof the output signal of the receiving amplifier 254 by thealternating-current signal from the oscillator 251, and sends out, tothe low-pass filter 260, a signal having a level corresponding to aphase difference between the output signal of the receiving amplifier254 and the alternating-current signal from the oscillator 251. Thelow-pass filter 260 has a cutoff frequency sufficiently lower than thefrequency f0. The low-pass filter 260 converts the output signal of thesynchronous detector 259 into a direct-current signal, and sends out thedirect-current signal to the sample and hold circuit 261. The sample andhold circuit 261 holds a voltage value of the output signal of thelow-pass filter 260 in predetermined timing, and sends out the voltagevalue to the A/D conversion circuit 262. The A/D conversion circuit 262converts the analog output of the sample and hold circuit 261 into adigital signal, and outputs the digital signal to the processing controlcircuit 263.

The processing control circuit 263 controls various parts of theposition detecting device 202. Specifically, the processing controlcircuit 263 controls the selection of a loop coil in the selectioncircuit 243, the switching of the switching connecting circuit 253, andthe timing of the sample and hold circuits 257 and 261. The processingcontrol circuit 263 makes a radio wave transmitted from the X-axisdirection loop coil group 241 and the Y-axis direction loop coil group242 for a certain transmission duration on the basis of the inputsignals from the A/D conversion circuits 258 and 262.

A radio wave transmitted from the electronic pen 1 generates an inducedvoltage in each of loop coils of the X-axis direction loop coil group241 and the Y-axis direction loop coil group 242. The processing controlcircuit 263 calculates the coordinate values of an indicated position inan X-axis direction and a Y-axis direction which position is indicatedby the electronic pen 1 on the basis of the level of the voltage valueof the induced voltage generated in each of the loop coils. In addition,the processing control circuit 263 detects a pen pressure on the basisof the level of the signal corresponding to the phase difference(frequency shift) between the transmitted radio wave and the receivedradio wave. Further, the processing control circuit 263 detects whetherthe side switch 104 is in an on state or in an off state on the basis ofthe level of the signal corresponding to the phase difference (frequencydifference) between the transmitted radio wave and the received radiowave.

Other Embodiments

The above description has been made of a case where the presentdisclosure is applied to an electromagnetic induction type electronicpen. However, the present disclosure is also applicable to an activecapacitive pen, which is an example of a capacitive type electronic pen.In an electronic pen as an example of the active capacitive pen to bedescribed in the following, a coil wound around a ferrite core is a partof a charging circuit that charges a power supply of a signaltransmission circuit included in the active capacitive pen.

FIG. 11 shows an example of circuit configuration of an electronic pen1B having a configuration of the active capacitive pen in the presentexample. In the electronic pen 1B having the configuration of the activecapacitive pen, a core body 3B has the constitution of an electrode coreformed of a conductor, for example, a conductive metal or a hard resinmixed with a conductive powder. In the following description, the corebody 3B will be referred to as an electrode core 3B.

Incidentally, though not shown, in the electronic pen 1B, a barrier 822of a pen pressure transmission member 82 is formed by a conductivemember, and a pressing member 7 is also formed by a member havingconductivity. An insulating film for insulation from the pen pressuretransmission member 82 is formed on a surface of a conductive elasticbody 833 of a pressure sensor 83 which surface corresponds to thebarrier 822. Terminal members configured as three-dimensional finepatterns as in the case of the terminal members 843 and 844 are formedon a holder 84 of a pen pressure detector 81 so as to be electricallyconnected to the barrier 822. The barrier 822 is configured to beelectrically connected to the terminal members when the pen pressuretransmission member 82 and the pen pressure detector 81 are engaged witheach other.

A signal transmission circuit (integrated circuit (IC)) that feeds theelectrode core 3B is provided on a board surface 10 a of a printedcircuit board 10. A connecting portion 842 of the holder 84 of the penpressure detector 81 is formed such that the terminal memberselectrically connected to the barrier 822 are electrically connected tothe signal transmission circuit.

In the present example, as shown in FIG. 11, an electronic circuitformed on the printed circuit board 10 has a circuit configurationincluding the above-described signal transmission circuit 301, anelectric double layer capacitor 302 as an example of a storage elementthat generates a driving voltage (power supply voltage) for driving thesignal transmission circuit 301, a rectifying diode 303, and a voltageconversion circuit 304. The signal transmission circuit 301 in thepresent example is formed by an oscillating circuit.

As in the foregoing embodiment, the electrode core 3B is insertedthrough a through hole 52 a of a ferrite core 52 of a coil member 5 andis fitted into the pressing member 7 having conductivity within the penpressure transmission member 82 of a pen pressure detector 8, andpresses the barrier 822 having conductivity via the pressing member 7having conductivity. The electrode core 3B is electrically connected tothe signal transmission circuit 301 on the printed board, as describedearlier.

As shown in FIG. 11, the two terminal members 843 and 844 of the penpressure detection module 8 are electrically connected to the signaltransmission circuit 301 formed on the printed circuit board. Theoscillating circuit constituting the signal transmission circuit 301generates a signal whose frequency changes according to the capacitanceof a variable capacitance capacitor 83BC of the pressure sensor 83 inthe pen pressure detector 81, and supplies the generated signal to theelectrode core 3B. In addition, the signal transmission circuit 301generates a signal whose frequency changes according to an on or offstate of the side switch 104, and supplies the generated signal to theelectrode core 3B.

When the electronic pen 1B in the present example is mounted on acharger not shown in the figures, an induced electromotive force isgenerated in a coil 51 due to an alternating magnetic field generated bythe charger, and charges the electric double layer capacitor 302 via thediode 303. The voltage conversion circuit 304 converts a voltage storedin the electric double layer capacitor 302 to a fixed voltage, andsupplies the fixed voltage as power to the signal transmission circuit301.

When the electronic pen 1B as a capacitive type stylus pen in thepresent example performs normal operation (when the electronic pen 1Bdoes not perform charging operation), the coil 51 is at a fixedpotential (ground potential (GND) in the present example), and thereforeacts as a shield electrode provided around the periphery of theelectrode core 3B. Incidentally, the fixed potential of the coil 51 whenthe capacitive type stylus pen performs normal operation is not limitedto the ground potential, but may be a positive side potential of thepower supply, or may be a potential intermediate between the positiveside potential of the power supply and the ground potential.

The signal transmission circuit (oscillating circuit) 301 generates asignal whose frequency changes according to the capacitance of thevariable capacitance capacitor 83BC formed by the pressure sensor 83 ofthe pen pressure detector 81 or a signal whose frequency changesaccording to an on or off state of the side switch 104, and supplies thegenerated signal to the electrode core 3B. The signal from the signaltransmission circuit 301 is radiated from the electrode core 3B as anelectric field based on the signal. The oscillating circuit constitutingthe signal transmission circuit 301 is formed by aninductance-capacitance (LC) oscillating circuit using resonance by acoil and a capacitor, for example. A position detecting device thatdetects the coordinate position of the capacitive type stylus pen as anexample of the electronic pen 1B according to the present embodiment candetermine a pen pressure applied to the electrode core 3B on the basisof the frequency of the signal.

FIG. 12 is a block diagram of assistance in explaining a positiondetecting device 400 that receives the signal from the electronic pen 1Bhaving the configuration of the capacitive type stylus pen, and detectsa position on a sensor and detects a pen pressure.

As shown in FIG. 12, the position detecting device 400 according to thepresent embodiment is constituted of a sensor 410 and a pen detectingcircuit 420 connected to the sensor 410. Though a sectional view of thesensor 410 is omitted in the present example, the sensor 410 is formedby stacking a first conductor group 411, an insulating layer (notshown), and a second conductor group 412 in order from a bottom layerside. The first conductor group 411 is, for example, a plurality offirst conductors 411Y₁, 411Y₂, . . . , 411Y_(m) (m is an integer of oneor more) that extend in a horizontal direction (X-axis direction) andwhich are arranged in parallel with each other in a Y-axis direction soas to be separated from each other at predetermined intervals.

The second conductor group 412 is a plurality of second conductors412X₁, 412X₂, . . . , 412X_(n) (n is an integer of one or more) thatextend in a direction intersecting the extending direction of the firstconductors 411Y₁, 411Y₂, . . . , 411Y_(m), or in a vertical direction(Y-axis direction) orthogonal to the extending direction of the firstconductors 411Y₁, 411Y₂, . . . , 411Y_(m) in the present example, andwhich are arranged in parallel with each other in the X-axis directionso as to be separated from each other at predetermined intervals.

Thus, the sensor 410 of the position detecting device 400 has aconfiguration that detects a position indicated by the electronic pen 1Bby using a sensor pattern formed by making the first conductor group 411and the second conductor group 412 intersect each other.

Incidentally, in the following description, when each conductor of thefirst conductors 411Y₁, 411Y₂, . . . , 411Y_(m) does not need to bedistinguished from the other conductors, the conductor will be referredto as a first conductor 411Y. Similarly, when each conductor of thesecond conductors 412X₁, 412X₂, . . . , 412X_(n) does not need to bedistinguished from the other conductors, the conductor will be referredto as a second conductor 412X.

The pen detecting circuit 420 includes a selection circuit 421 as aninput-output interface with the sensor 410, an amplifier circuit 422, aband-pass filter 423, a detecting circuit 424, a sample and hold circuit425, an A/D conversion circuit 426, and a control circuit 427.

The selection circuit 421 selects one conductor 411Y or 412X from thefirst conductor group 411 and the second conductor group 412 on thebasis of a control signal from the control circuit 427. The conductorselected by the selection circuit 421 is connected to the amplifiercircuit 422. A signal from the electronic pen 1B is detected by theselected conductor, and is amplified by the amplifier circuit 422. Theoutput of the amplifier circuit 422 is supplied to the band-pass filter423, where only a frequency component of the signal transmitted from theelectronic pen 1B is extracted.

The output signal of the band-pass filter 423 is detected by thedetecting circuit 424. The output signal of the detecting circuit 424 issupplied to the sample and hold circuit 425 to be sampled and held inpredetermined timing according to a sampling signal from the controlcircuit 427, and is thereafter converted into a digital value by the A/Dconversion circuit 426. The digital data from the A/D conversion circuit426 is read and processed by the control circuit 427.

The control circuit 427 operates so as to send out respective controlsignals to the sample and hold circuit 425, the A/D conversion circuit426, and the selection circuit 421 according to a program stored in aninternal read-only memory (ROM). From the digital data from the A/Dconversion circuit 426, the control circuit 427 calculates positioncoordinates on the sensor 410 which position coordinates are indicatedby the electronic pen 1B, and detects a pen pressure detected by the penpressure detector of the electronic pen 1B.

As a flow of operation, the control circuit 427 supplies a selectionsignal to the selection circuit 421 to select each of the secondconductors 412X, and reads data output from the A/D conversion circuit426 as a signal level.

When a signal having a level equal to or higher than a predeterminedvalue is detected from any of the second conductors 412X, the controlcircuit 427 stores the numbers of a second conductor 412X from which ahighest signal level is detected and a plurality of second conductors412X adjacent to the second conductor 412X from which the highest signallevel is detected. Similarly, the control circuit 427 controls theselection circuit 421, and stores the numbers of a first conductor 411Yfrom which a highest signal level is detected among the first conductors411Y and a plurality of first conductors 411Y adjacent to the firstconductor 411Y from which the highest signal level is detected.

Then, the control circuit 427 detects a position on the sensor 410 whichposition is indicated by the electronic pen 1B from the numbers of thesecond conductors 412X and the numbers of the first conductors 411Ywhich numbers are stored as described above.

In addition, the control circuit 427 detects the frequency of a signalfrom the A/D conversion circuit 426, and detects a pen pressure valuedetected by the pen pressure detector 81 of the electronic pen 1B fromthe detected frequency. Specifically, as described earlier, theoscillation frequency of the oscillating circuit constituting the signaltransmission circuit 301 of the electronic pen 1B is a frequencycorresponding to the capacitance of the variable capacitance capacitor83BC formed by the pressure sensor 83 of the pen pressure detector 81.The control circuit 427, for example, has the information of acorrespondence table of oscillation frequencies of the oscillatingcircuit constituting the signal transmission circuit 301 of theelectronic pen 1B and pen pressure values, and detects a pen pressurevalue from the information of the correspondence table.

Incidentally, in the above-described example, the electronic pen 1Bconverts the pen pressure detected by the pressure sensor 83 of the penpressure detector 81 into a frequency, and supplies the frequency to theelectrode core 3B. However, a signal attribute to which the pen pressureis made to correspond is not limited to the frequency, but the penpressure may be made to correspond to the phase of the signal, thenumber of times of interruption of the signal, or the like.

In addition, while the coil 51 wound around the ferrite core is used asa coil for charging in the electronic pen 1B having the configuration ofthe active capacitive pen in the above-described example, a cell(battery) may be included as a source of supply of the power supplyvoltage for the signal transmission circuit 301. In that case, theferrite core wound with the coil is not necessary. Then, in that case, aconstitution can be formed in which a hollow tubular body constituting ashield electrode for the electrode core 3B is provided in place of thecoil member, and the tubular body is fitted to the pen pressuretransmission member 82 via a holding member for the tubular body.

In addition, in the electronic pen 1B having the configuration of theactive capacitive pen in the above-described example, the signaltransmission circuit 301 is configured as only the oscillating circuit,and a pen pressure is transmitted as a change in the oscillationfrequency of the oscillating circuit to the position detecting device.However, the signal transmission circuit may be formed by an oscillatingcircuit and a circuit that applies a predetermined modulation to theoscillating signal of the oscillating circuit, and pen pressureinformation may be transmitted as for example an amplitude-shift keying(ASK) signal or the like to the position detecting device.

Other Embodiments or Modifications

In the foregoing embodiment, the case 2 is the external casing of theelectronic pen. However, the above-described case 2 may be a case(casing) of an electronic pen cartridge housed within an external casingof an electronic pen. In that case, a waterproof property and adustproof property of the electronic pen cartridge are ensured, andthere is no need for a sealing constitution related to a waterproofproperty and a dustproof property for the external casing of theelectronic pen. In the case of the constitution of the electronic pencartridge, the electronic pen cartridge can be configured as apush-action refill. In that case, an end portion of the case (casing) ofthe electronic pen cartridge which end portion is on an opposite sidefrom a pen tip side of the case (casing) has the constitution of afitting portion fitted to a push mechanism.

In the foregoing embodiment, the variable capacitance capacitor formedby the pressure sensor of the pen pressure detector is not limited tovariable capacitance capacitors having a mechanical constitution formedby combining a plurality of parts as in the above-described example, butcan have a one-part constitution using a semiconductor element whosecapacitance is variable according to a pen pressure, as disclosed inJapanese Patent Laid-Open No. 2013-161307, for example.

In addition, the pressure sensor of the pen pressure detector in theforegoing embodiment uses the variable capacitance capacitor whosecapacitance is variable according to a pen pressure. However, it isneedless to say that the pressure sensor of the pen pressure detectormay make variable an inductance value or a resistance value as achanging element that changes the resonance frequency of the resonancecircuit.

It is to be noted that the embodiment of the present disclosure is notlimited to the foregoing embodiments, and that various changes can bemade without departing from the spirit of the present disclosure.

What is claimed is:
 1. An electronic pen comprising: a casing; anopening portion formed on one side of the casing; a core body thatprojects outside of the casing through the opening portion; a circuitboard; and a core body insertion member disposed in the casing andhaving a hollow space that houses the core body, the hollow spaceincluding a hollow portion between an inner circumferential surface ofthe core body insertion member and an outer circumferential surface ofthe core body when the core body insertion member houses the core body,the hollow portion communicating, via the opening portion, with a firstspace external to the electronic pen, and the hollow portion separatedfrom a second space in which the circuit board is disposed.
 2. Theelectronic pen according to claim 1, further comprising: a pen pressuredetector which, in operation, detects a pen pressure applied to the corebody, wherein the core body insertion member has a barrier thatseparates the hollow portion from the pen pressure detector and thebarrier is adjacent to the pen pressure detector.
 3. The electronic penaccording to claim 2, wherein, in operation, the pen pressure applied tothe core body is transmitted to the pen pressure detector by elasticdisplacement of the barrier based on movement of the core body accordingto the pen pressure.
 4. The electronic pen according to claim 2, whereinthe barrier is formed by an elastic member.
 5. The electronic penaccording to claim 2, wherein a pressing member is fitted on a side ofthe core body, and the core body presses the barrier of the core bodyinsertion member, via the pressing member, according to the penpressure.
 6. The electronic pen according to claim 1, furthercomprising: a pen pressure detector which, in operation, detects a penpressure applied to the core body and being coupled to the core bodyinsertion member.
 7. The electronic pen according to claim 1, wherein asealing member separates the hollow portion from the second space. 8.The electronic pen according to claim 1, wherein a sealing member isdisposed between the first space and the second space.
 9. The electronicpen according to claim 1, wherein a magnetic core houses the core bodyand a sealing member is disposed on the magnetic core.
 10. Theelectronic pen according to claim 9, wherein the sealing member is acap-shaped elastic member.
 11. The electronic pen according to claim 1,further comprising: a pen pressure detector which, in operation, detectsa pen pressure applied to the core body, wherein the circuit boarddisposed on a first side of the pen pressure detector, the first sidebeing opposite to a second side of the pen pressure detector, the corebody insertion member being disposed on the second side of the penpressure detector, wherein a coupling portion that couples the circuitboard to the pen pressure detector, and wherein a sealing member thatcloses a gap between the coupling portion and an inner wall of thecasing.
 12. The electronic pen according to claim 11, wherein thecircuit board is disposed in a board holder and the board holder has afitting portion fitted to the pen pressure detector, and the sealingmember is formed on the fitting portion of the board holder.
 13. Theelectronic pen according to claim 12, wherein a terminal of the penpressure detector is connected to the circuit board retained in theboard holder through the fitting portion of the board holder, and acapacitor connected in parallel with the coil constituting a resonancecircuit is disposed on the circuit board.
 14. The electronic penaccording to claim 1, further comprising a pen pressure detector which,in operation, detects a pen pressure applied to the core body, whereinthe circuit board including a switch configured to be depressed by apressing member, and wherein a coupling portion that couples the circuitboard to the pen pressure detector, the coupling portion provided with asealing member that closes a gap between the coupling portion and aninner wall of the casing.
 15. The electronic pen according to claim 1,further comprising: a pen pressure detector which, in operation, detectsa capacitance that changes according to a pen pressure applied to thecore body.
 16. The electronic pen according to claim 1, furthercomprising: a pen pressure detector which, in operation, detects a penpressure applied to the core body, wherein the circuit board is disposedon a first side of the pen pressure detector, the first side beingopposite to a second side of the pen pressure detector, the core bodyinsertion member being disposed on the second side of the pen pressuredetector, and wherein an electronic part mounting surface of the circuitboard is covered by a molded member.